Very first OnAppearing animations doesn't work

The issue is reproduced both on Android and iOS.

The application's first content page has animations in the OnAppearing method.

When I start the application, it seems like the page's OnAppearing method is being called in parallel with the Splash screen or something. Anyway, it results with no animations in the first appearing.

Then, navigating to another page and back shows the animations great.

Any idea or advice with this subject? Thanks!